<h1 class="display-4 md-4">添加<span class="h4"><mark class="text-info ml-3">base</mark></span></h1>
<form action="/add" method="POST">
    <div class="form-group">
        <input type="text" name="thing" class="form-control form-control-lg" placeholder="请添加内容">
    </div>
    <input type="submit" value="添加" class="btn btn-dark btn-lg">
    <a href="/" class="btn btn-danger btn-lg"> 取消</a>
</form>